It is known in the art of position sensors to use a potentiometer to produce an output signal that is a function of the position of a particular component. For example, U.S. Pat. No. 4,915,075 (the '075 patent) describes a potentiometer used as an accelerator pedal position sensor. The '075 patent discloses a potentiometer having a movable wiper in contact with a stationary portion. The stationary portion includes a two sided circuit board, one side of which includes a resistive strip and a conductive strip. The other side includes discrete pulse-width-modulation conditioning circuitry that converts the analog potentiometer signal into a pulse-width-modulated signal which is a function of the accelerator pedal position.
The position sensor disclosed in the '075 patent has advantages over prior art accelerator pedal position sensors, but it also has several drawbacks. One drawback involves the manufacture of a printed circuit board that includes a resistive strip. The manufacturing process for making the resistive strip sometimes conflicts with the manufacturing processes for a printed circuit board, and may degrade the electrical runs on the printed circuit board and cause the board to fail. It would be preferable to develop a printed circuit board such that the manufacturing process for the resistive strip does not damage the printed circuit board.
A further drawback of the position sensor disclosed in the '075 patent is the relatively large amount of space required by the discrete pulse-width-modulation conditioning circuitry. It would be preferable to implement conditioning circuitry that requires less space.
Most position sensors are designed to function over a specific range of angles. Because the resistive element of the '075 patent is fixed on the circuit board, the potentiometer can measure a maximum angle determined by the arc of the resistive element. The potentiometer may not be used in applications requiring the measurement of angles larger than that maximum. It would be preferable to use a potentiometer having a plurality of such maximum angles, where the maximum angle could be selected according to the specific application.
The present invention is directed toward overcoming one or more of these drawbacks.